We live in a 3 bed Victorian terraced house in Kent - we could NEVER afford anything like this in London, regardless of the Zone, full stop. My husband works from home and I work in London. Granted, I pay over £3,000 per year on my annual season train + tube ticket. But I'm also making £7,500 more per year this year than I could make "close to home".
You have to weigh out what's important to you. For us, it was owning our own home after 4 years of renting. And as I'm the only one who has to worry about travel, it seemed a no-brainer.
I would much rather this commute - approximately 1.5 hours by train & tube/bus where I don't have to worry about the driving and can read or sleep or whatever - than the one I used to do in Florida, driving 45 minutes to up to three hours each way. And, interestingly (or not!) I cook a "real" dinner 4 out of 5 nights when I get home, unlike my usual M.O. in Florida which was drive-thru meals 4 out of 5, as I couldn't be bothered to cook when I got in.
Again, it all depends on what you want to spend your money/time on. We're 45 minutes away from Victoria if we want to come into London at the weekend, the times of the last trains haven't been a problem so far and we're close enough to the coastal towns for get-aways.